Synchronous motor clock



Oct.10,1933. w. A. SPEAR 1,930,289

SYNCHRONOUS MOTOR CLOCK Filed Nov. 24, 1930 2 Sheets-Sheet l ji zfijfl ca C3 z "1 ]@1 @2 I A A- l I I I l s.

[72 V672 for Patented Oct. 10, 1933 SYNCHRONOUS MOTOR CLOCK Walter A.Spear, Cincinnati, Ohio, assignor, by

mesne assignments, to Victor Electric Products, Inc., Cincinnati, Ohio,a corporation of Ohio Ap lication November 24, 1930 Serial No. 497,646

'1 Claim. (01. 172-275) My invention relates to a synchronous motor oralternating current clock, and to a motor therefor, and has for oneobject the provision of a clock which maybe operated by a synchronousmotor in circuit with a commercial source or supply of alternatingcurrent, One object of my invention is the provision of such a clockwhich shall be efficient and regular. Another object 1s the provision ofimproved means forrendering such a clock readily started manually.Another object is the provision of means for preventing hunting. Otherobjects will appear from time to time in the ,course of thespecification and claim.

I illustrate my invention more or less diagrammatically in theaccompanying drawings, where Figure 1 is an elevation; Figure 2 is asection on the line 22 of Figure 1;

Figure 3 is a section on the Figure 2;

Figure 4 is a detail; Figure 5 is a section on the line 5-5 of Figure 4;Figure 6 is a detail of a variant form;

Figure '7 is a section on the line 77 of Figure 20 line 3-3 of Figure 8is a partial section through a variant form: Figure 9 is a section onthe line 9-9 of Figure 8;

' Figure 10 is a detail;

Figure 11 is a detail; and Figure 12 Ba section on the line 12-12 ofFigure 11.

v Like parts are indicated by like symbols throughout specification anddrawings.

Referring to the drawings, A generally indicates a clock base, on whichmay be mounted a 40 housing structure which includes side panels A Aconnected by an arcuateintermediate wall. overlying said wall. is afront and rear panel or strip A having inturned ends A which may besecured to the base, as by the bolts A It will be understood that thesurrounding strip A clamps the housing structure which includes thepanels A A and arcuate wall A upon the base A. I illustrate the edges ofthe panels A A as rolled over as at' A" which project beyond the edgesof the strip A A is an indicating aperture in one side of the panel A*,the edges of which are formedas indicating fingers, as at A. An apertureA" in the wall A is in register with the aperture A a 5 Positioned onthe inner face of the panel A vention,!ut it will be understood thatthrough are a plurality of relatively thick plates B, to which may besecured combined pole pieces and. clock supports'B the pole pieces beingprovided with angles or outwardly projecting offsets l? at their lowerends, connected by the laminated '00 member B about which is the coil 13in circuit as by conductive lines B 1?, with any suitable source ofalternating current.

Secured to the upper ends of the pole pieces B is an oil-tight housing,including the housing or cup member C and a lid or front C therefor, theedges of the members C and C being secured together, for examplesoldered, as at C Positioned within the housing C is the rotor C beingindicated as having a plurality of teeth 0* opposed to teeth C on thepole pieces C secured to and in effect forming part of the pole pieces BThe inner pole pieces C are positioned inside of the housing C, whichare connected to the exterior pole pieces, for example by bolts orrivets C". The relation of the inner pole pieces C and the rotor C willbe clear from Figure 2. The rotor C is mounted on a shaft C rotating insuitable bearings (3' and terminating, exteriorally of the housing C, ina knurled knob 0 This knob is positioned exteriorally of the panel A3,the panel being apertured as at C to permit its passage ,therethrough.

D is a pinion on the rod C in mesh with a gear D on the shaft D Thedetails of the clock mechanism or train 0 gears herein shown do not ofthemselves form part of the present inthetrai of gears, including thepinion D, the gear D nd other pinions D and gears D on the shafts D andD respectively, rotation of the rotor C and the shaft C effects rotationof the drum D The gears D and associated pinions D are loosely mountedupon the shafts U D In mesh with one 'of the pinions D upon the shaft Dis the gear D fixed in relation with the shaft D Mounted for rotationwith the shaft D exterior of the housing 0 is the driving pinion D inmesh with the gear I) upon the stub shaft p The final driving con- 10onection is through the associated pinion D meshing with the gear D fixedin relation tov the sleeve D which serves to support and center the drumD and fix its axis of rotation. The sleeve D is mounted upon and free torotate independently of'rotation of the shaft D. The shaft D is alsoprovided with an exterior knob D whereby a 'more rapid rotation of thedrum -may be provided than is obtained through the normal rotation ofthe rotor (P. This permits the setting 01' the drum at any desiredposition, and thus permits setting of the time indicating means, whencorrection is necessary.

Mounted upon the shaft and rotatable thereabout is the sleeve E which isconfined between spacers E E. Interposed between the spacer E and thesleeve E is the member E fixed upon the shaft C, for example by apressed fit. It may be of steel or other material susceptible toattraction by a magnet. Rotatable with the sleeve E about the shaft Cand spaced from the member E as by the shoulder E is the permanentmagnet E which may be of magnetic steel. Opposite the ends of the i5magnet E the member E is offset, as at E to extend into the plane of themagnet and closely to approach the ends of the magnet.

Referring to the variant form of Figures 6 and 7, the magnet E isprovided with terminal portions or teeth G which extend forwardly intoan aperture G in the offset ends E of the member E As will be seen fromFigure 6, the clearance of the members G within the aperture G issuflicient to permit a substantial rotation of the magnet E in relationto the member E. In the form of Figures 6 and 7 the member E is also apermanent magnet, and normally the teeth G are held in central positionin the aperture G by the repulsion of like poles of the so two magnets.

Referring to the form of Figure 8 and following, I mount the member H,susceptible toattraction by a magnet, the member H including a disc Hwith the teeth H upset or oifset therefrom. The member H is held againstrotation in relation to the shaft C". Mounted for rotation upon theshaft C is a magnetic member generally indicated as I which includes twostar members I 1*. Each such star member includes a hub 1 and aplurality of arms or teeth 1* radially extending therefrom. The partsare so proportioned that when the star members I P are secured togetheras a unit, for example a by the sleeve 1, the teeth of the two starsalternate, as shown in Figure 9. Each alternate tooth is of difierentpolarity.

It will be realized that whereas I have described and shown a practicaland operative device, nevertheless many changes may be made in size;shape, number and distribution of parts. I therefore wish my drawingsand description to be taken as in a broad sense illustrative and dietgrammatic, rather than as limiting me to the precise features andlimitations herein described and shown. In particular I wish it to beunderstood that the precise details of the synchronous motor hereinshowndo not of themselves form part of the present invention. and I donot wish my present inertia member 00v to limit itto use with asynchronous motor clock' or to use with the particular clock hereinshown, except so far as. I precisely limit myself by the suaseor myclaim.

, The use and operation of my invention are as follows:

me coil 3 being in circuit with commercially p ied alternating current,tnea temation at the current through the pole pieces B and C causesarotation of the rotor C and the shaft C in step with the alternatingcurrent supply. This rotation of the rotor C and shaft C causes arotation of the drum D Rotation of the drum causes movement of the timeindicating symbol D in line with the aperture A and past the indicatingfingers A. The alternating current motor may be launched, for example,by manual rotation of the knob 0 and if launched at a speedapproximately that or somewhat greater than synchronous, it willcontinue rotation indefinitely unless and until the circuit through thecoil B is interrupted or broken.

In order to set the drum, for example to compensate a stoppage of theclock, the operator rotates a knob D which eiIects a rather rapidrotation of the drum and permits it to be readily set. The intertiamember above described aids in the manual launching of the clock andprevents hunting during operation.

In the forms herein shown, the member E tends magnetically to hold apredetermined and normally fixed relationship to the member E.

A sudden change in the velocity of the rotation 10 of the shaft E tendsto move the member E in relation to the magnetic inertia member E. Themagnetic drag thereupon operates to pull the two members back into theirpredetermined normal relationship, and the result is a resistance tochanges oi rotation of the rotor as a whole and a prevention of theso-called hunting of the rotor.

I find the formshown in Figure 8 and following to be a particularlyefficient embodiment of my invention, the magnetic drag between theteeth of the stars I I and the teeth of the member B being eflicientnormally to tend to maintain the two members normally in their fixedrelationship. The device is effective both l to prevent hunting and toassist in ready starting of the device when launched at a speed somewhatgreater than synchronism. This structure may be referred to as a loosecoupling although it is not at all to be considered as the 3 sort ofdevice described as loose couplings in mechanical structures. This typeof coupling is a loose coupling electro-magnetically. Its primaryfunction is to permit of automatic or selfadjustment in an electricdrive which is necessary to compensate for slight either in the electricimpulses or in mechanical system which will tend to throw a synchronousdrive out of step or out of synchronism.

I claim:

In a synchronous electric motor, an alternating magnetic field circuit,a rotor adapted to be influenced by-the field, means outside the heldand rotor for opposing changes in angular velocity of said rotor, saidmeans including memhas adapted to act upon each other magnetically andadapted to oppose relative motion with relation to each other largely bymagnetic force,

one of said members being rigidly connected to up -m the rotor.

WALTER-A. SPEAR.

